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A new gymnophthalmid lizard of the genus Anadia Gray, 1845 is described from the summit of Abakapá-tepui, Bolívar State, Venezuela, between 2200-2242 m elevation. The new species, Anadia mcdiarmidi sp. nov., is endemic to the Chimantá Massif and seemingly also occurs on Amurí-tepui and Murei-tepui. The new taxon is mainly distinguished from all known congeners by the following combination of characters: body fairly robust, dorsal scales small and quadrangular, middorsal scales 53-57, suboculars large, subequal in size, with sometimes one scale slightly protruding downward between 4th and 5th supralabial, nasal entire, without sub-nostril groove, body uniform beige or greyish to bluish brown in life, devoid of any conspicuous pattern in males, venter immaculate golden grey in life, femoral pores 9-10 on each side in males, preanal pores absent, hemipenis globose, weakly bilobed, bordered by numerous fl ounces (>20) bearing comblike rows of minute weakly mineralized spinules. The presence of a species of Anadia, a primarily Andean genus, on the top of tepuis is of considerable interest to the understanding of the Pantepui biogeography.
The frog Pristimantis marmoratus was originally described als Hylodes marmoratus by George A. Boulenger in 1900 based on a single specimen reported to have been collected at the foot of Mount Roraima in Guyana in 1898. We herein discuss the exact location of the type locality of P. marmoratus and provide a redescription of the species based on new material from Kaieteur National Park and from the slopes of Maringma-tepui in Guyana. We also describe the previously unknown vocalization and breeding ecology of the species, and conducted an exploratory molecular analysis of the phylogenetic relationships within the genus Pristimantis represented by the members of the "unistrigatus species group" in the Guiana Shield. Pristimantis marmoratus is a small-sized species mainly distinguished from its known Guiana Shield congeners by the combination of F I < II, SVL ≤ 20.4 in males, presence of vocal slits in males, granular/pustulate dorsal skin with well-developed scapular ridges, basal webbing between fingers, fringes in fingers and toes, crossed iris, diffuse yellow or pale green wash on groin, and absence of flashy colour on axillary/pre-axillary region. The advertisement call consists of a single note repeated at a rate of ca 11 calls/min with a dominant frequency ranging from 2756 to 3101 Hz. Pristimantis marmoratus is primarily arboreal, exclusively active at dusk, and propably restricted to the pristine rainforests of the Pantepui uplands and highlands, east of the Gran Sabana between ca 600 and 1800 m above sea level. Preliminary molecular analyses recovered Pristimantis marmoratus as sister to an unnamed species from the Eastern Guiana Shield. On grounds of the newly established distributional extent we suggest maintaining the IUCN conservation status as Least Concern.
Species distributed across vast continental areas and across major biomes provide unique model systems for studies of biotic diversification, yet also constitute daunting financial, logistic and political challenges for data collection across such regions. The tree frog Dendropsophus minutus (Anura: Hylidae) is a nominal species, continentally distributed in South America, that may represent a complex of multiple species, each with a more limited distribution. To understand the spatial pattern of molecular diversity throughout the range of this species complex, we obtained DNA sequence data from two mitochondrial genes, cytochrome oxidase I (COI) and the 16S rhibosomal gene (16S) for 407 samples of D. minutus and closely related species distributed across eleven countries, effectively comprising the entire range of the group. We performed phylogenetic and spatially explicit phylogeographic analyses to assess the genetic structure of lineages and infer ancestral areas. We found 43 statistically supported, deep mitochondrial lineages, several of which may represent currently unrecognized distinct species. One major clade, containing 25 divergent lineages, includes samples from the type locality of D. minutus. We defined that clade as the D. minutus complex. The remaining lineages together with the D. minutus complex constitute the D. minutus species group. Historical analyses support an Amazonian origin for the D. minutus species group with a subsequent dispersal to eastern Brazil where the D. minutus complex originated. According to our dataset, a total of eight mtDNA lineages have ranges >100,000 km2. One of them occupies an area of almost one million km2 encompassing multiple biomes. Our results, at a spatial scale and resolution unprecedented for a Neotropical vertebrate, confirm that widespread amphibian species occur in lowland South America, yet at the same time a large proportion of cryptic diversity still remains to be discovered.